TIR-domain-containing adapter-inducing interferon-β (TRIF) forms filamentous structures, whose pro-apoptotic signalling is terminated by autophagy

TY - JOUR

T1 - TIR-domain-containing adapter-inducing interferon-β (TRIF) forms filamentous structures, whose pro-apoptotic signalling is terminated by autophagy

AU - Gentle, Ian E

AU - McHenry, Kevin T

AU - Weber, Arnim

AU - Metz, Arlena

AU - Kretz, Oliver

AU - Porter, Dale

AU - Häcker, Georg

N1 - © 2017 Federation of European Biochemical Societies.

PY - 2017/7

Y1 - 2017/7

N2 - The formation of amyloid-like protein structures has recently emerged as a feature in signal transduction, particularly in innate immunity. These structures appear to depend on defined domains for their formation but likely also require dedicated ways to terminate signalling. We, here, define the innate immunity protein/Toll-like receptor adaptor TIR-domain-containing adapter-inducing interferon-β (TRIF) as a novel platform of fibril formation and probe signal initiation through TRIF as well as its termination in Toll-like receptor 3 (TLR3)-stimulated melanoma cells. A main signalling pathway triggered by TLR3 caused apoptosis, which was controlled by inhibitor of apoptosis proteins and was dependent on RIPK1 and independent of TNF. Using correlative electron/fluorescence microscopy, we visualised fibrillar structures formed through both Toll/interleukin-1 receptor and RIP homotypic interacting motif regions of TRIF. We provide evidence that these fibrillary structures are active signalling platforms whose activity is terminated by autophagy. TRIF-signalling enhanced autophagy, and fibrillary structures were partly contained within autophagosomes. Inhibition of autophagy increased levels of pro-apoptotic TRIF complexes, leading to the accumulation of active caspase-8 and enhanced apoptosis while stimulation of autophagy reduced TRIF-dependent death. We conclude that pro-death signals through TRIF are regulated by autophagy and propose that pro-apoptotic signalling through TRIF/RIPK1/caspase-8 occurs in fibrillary platforms.

AB - The formation of amyloid-like protein structures has recently emerged as a feature in signal transduction, particularly in innate immunity. These structures appear to depend on defined domains for their formation but likely also require dedicated ways to terminate signalling. We, here, define the innate immunity protein/Toll-like receptor adaptor TIR-domain-containing adapter-inducing interferon-β (TRIF) as a novel platform of fibril formation and probe signal initiation through TRIF as well as its termination in Toll-like receptor 3 (TLR3)-stimulated melanoma cells. A main signalling pathway triggered by TLR3 caused apoptosis, which was controlled by inhibitor of apoptosis proteins and was dependent on RIPK1 and independent of TNF. Using correlative electron/fluorescence microscopy, we visualised fibrillar structures formed through both Toll/interleukin-1 receptor and RIP homotypic interacting motif regions of TRIF. We provide evidence that these fibrillary structures are active signalling platforms whose activity is terminated by autophagy. TRIF-signalling enhanced autophagy, and fibrillary structures were partly contained within autophagosomes. Inhibition of autophagy increased levels of pro-apoptotic TRIF complexes, leading to the accumulation of active caspase-8 and enhanced apoptosis while stimulation of autophagy reduced TRIF-dependent death. We conclude that pro-death signals through TRIF are regulated by autophagy and propose that pro-apoptotic signalling through TRIF/RIPK1/caspase-8 occurs in fibrillary platforms.

KW - Adaptor Proteins, Vesicular Transport

KW - Animals

KW - Apoptosis

KW - Autophagy

KW - Blotting, Western

KW - Caspase 8

KW - Cell Line, Tumor

KW - Cells, Cultured

KW - HEK293 Cells

KW - HeLa Cells

KW - Humans

KW - Mice, Knockout

KW - Microscopy, Electron, Transmission

KW - Microscopy, Fluorescence

KW - Oligopeptides

KW - Poly I-C

KW - Receptor-Interacting Protein Serine-Threonine Kinases

KW - Signal Transduction

KW - Toll-Like Receptor 3

KW - Journal Article

U2 - 10.1111/febs.14091

DO - 10.1111/febs.14091

M3 - SCORING: Journal article

C2 - 28453927

VL - 284

SP - 1987

EP - 2003

JO - FEBS J

JF - FEBS J

SN - 1742-464X

IS - 13

ER -